Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/16—Organic compounds
  • C11D3/37—Polymers
  • C11D3/3746—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C11D3/3757—(Co)polymerised carboxylic acids, -anhydrides, -esters in solid and liquid compositions
  • C11D3/3765—(Co)polymerised carboxylic acids, -anhydrides, -esters in solid and liquid compositions in liquid compositions
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
  • A61K8/30—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds
  • A61K8/46—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds containing sulfur
  • A61K8/463—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds containing sulfur containing sulfuric acid derivatives, e.g. sodium lauryl sulfate
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
  • A61K8/30—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds
  • A61K8/46—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds containing sulfur
  • A61K8/466—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds containing sulfur containing sulfonic acid derivatives; Salts
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
  • A61K8/72—Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds
  • A61K8/81—Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • A61K8/8141—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • A61K8/8147—Homopolymers or copolymers of acids; Metal or ammonium salts thereof, e.g. crotonic acid, (meth)acrylic acid; Compositions of derivatives of such polymers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61Q—SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
  • A61Q5/00—Preparations for care of the hair
  • A61Q5/02—Preparations for cleaning the hair
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F290/00—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups
  • C08F290/02—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups on to polymers modified by introduction of unsaturated end groups
  • C08F290/06—Polymers provided for in subclass C08G
  • C08F290/062—Polyethers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59

Definitions

• This invention relates to thickened aqueous solutions, and more particularly to a method of thickening low-pH, aqueous, surfactant-containing compositions, and the compositions so thickened.
• Additives for thickening are widely known, and include nonionic thickeners, exemplified by natural gums such as guar and locust bean extract, starches and cellulose and their derivatives, such as hydroxyalkyl celluloses and carboxyalkyl celluloses. They also include ionic thickeners, exemplified by certain polyelectrolyte resins such as polymers of acrylic acid and methacrylic acid, and copolymers containing hydrophobic groups based upon long, fatty-acid constituents and hydrophilic linkages based upon poly(oxyethylene) chains.
• the nonionic thickeners are relatively insensitive to pH, but they are also relatively expensive, require special processing techniques for incorporation into aqueous compositions, must be used in comparatively high concentration, and tend to exhibit viscosity loss on storage as a result of hydrolysis.
• the ionic thickeners are therefore of greater interest, since they overcome many of these deficiencies.
• the alkali-soluble emulsion polymer thickeners which are supplied as acidic emulsions of relatively low viscosity, and are neutralized at least partially to the salt form either prior to, simultaneously with, or subsequent to incorporation into the aqueous compositions.
• the neutralization is accompanied by dissolution of the thickener emulsion, and by a marked increase in the thickener viscosity.
• the composition itself is neutral or alkaline, so this neutralization of the thickener emulsion presents no problem.
• the process of the present invention comprises the steps, performed in any order, of (a) mixing the alkali-soluble emulsion polymer thickener with an aqueous surfactant-containing solution, and (b) neutralizing the thickener, and the step, performed subsequent to the two above steps, of (c) adjusting the pH of the mixture to 7.0 or below, preferably between 7.0 and 1.2, and more preferably between 5.0 and 6.5.
• the thickeners of the present invention are alkali-soluble emulsion polymer thickeners, materials which, as produced, are non-water-soluble emulsions, but which dissolve and show a marked increase in viscosity on addition of alkali.
• the preferred thickeners are those described in U.S. patent application Ser. No. 101,615, filed Dec. 10, 1979, which is hereby incorporated herein by reference. While the preferred thickeners themselves and the method of preparing them are set forth in detail in that application, they are also briefly set forth below.
• the thickeners are aqueous dispersions of water-insoluble, emulsion copolymers obtained by aqueous emulsion copolymerization of the three following monomers, and optionally the fourth monomer, set forth below:
• R is H or CH 3 , the latter being preferred
• n is at least 2, and preferably has an average value of at least 10, up to 40 to 60 or even up to 70 or so, and
• R° is a hydrophobic group, for example an alkyl, alkylaryl, or polycyclic alkyl group having 8 to 30 carbon atoms, preferably 16 to 18 carbon atoms, or having an average of 12 to 18 or more carbon atoms,
• a C 1 -C 4 alkyl acrylate or methacrylate preferably ethyl acrylate, butyl acrylate or methyl methacrylate
• the emulsion copolymer dispersions obtained have solids contents from 25 to 50% by weight, and the 3-component copolymer dispersion has a weight-average molecular weight of about 100,000 to several million.
• the chain-transfer agent may be used to obtain molecular weights in the lower part of the range, or even down to about 80,000.
• use of 0.05% to about 1.0% of monomer component (4), based on total monomers, serves to provide molecular weights in or above the higher portion of the range mentioned.
• R° may be octyl (C 8 ), lauryl (C 12 ), tridecyl (C 13 ), myristyl (C 14 ), or pentadecyl (C 15 ), but preferably C 12 to C 18 or mixtures thereof, examples being lauryl, cetyl, palmityl, and stearyl.
• R° may be alkylaryl, such as octyl and vinylphenyl, or polycyclic alkyl such as cholesterol and lanosterol.
• a mixture of several C 8 -C 30 alkyl ethers may be used.
• These emulsion copolymers may be produced by conventional aqueous emulsion polymerization techniques, using appropriate emulsifiers for emulsifying the monomer and for maintaining the polymer obtained in a stable-dispersed condition. Additional information on the emulsion polymerization may be found in the above-referenced application.
• the amount of thickener to be used in the composition depends largely upon the degree of thickening desired. While high concentrations, as for instance, above 10% by weight of thickener, are operable, the viscosities obtained would be extremely high, and would therefore be expected to be both physically impractical and uneconomical.
• the preferred maximum level of thickener is therefore below 5%, and more preferably below 2.5%, by weight. The minimum level depends again primarily upon the degree of thickening desired, and it is expected that a measurable viscosity increase will occur at thickener levels as low as 0.05%.
• the thickeners of the present invention are water-insoluble, alkali-soluble emulsions having a milky appearance.
• a neutralizing agent as for example an alkali metal hydroxide, ammonium hydroxide, soda ash or triethanolamine
• the emulsion dissolves to form an essentially clear solution and the viscosity increases sharply.
• most aqueous thickener solutions will coagulate and revert to low-viscosity suspensions.
• the thickener solution neutralized as described above shall be referred to herein as "activated".
• an activated thickener acidified in the absence of a surfactant shall be considered to have lost its activation, while an activated thickener which is acidified in the presence of a surfactant as described below, and which retains a significant amount of its thickening power, shall continue to be considered an activated thickener.
• the surfactants useful in the present invention generally include those anionic, nonionic and amphoteric surfactants which are compatible with the thickener used, that is, which cause no precipitation of the thickener in the solution.
• Common surfactants may be used, including but not limited to, sodium, ammonium and amine salts of fatty alcohol sulfates and fatty alcohol ether sulfates, alkanol ethoxylates, alkyl phenyl ethoxylates, alkanolamides, and alpha olefin sulfonates.
• the surfactant level required in the present invention is at least about 5% by weight, and more preferably at least about 10% by weight.
• the maximum surfactant level depends upon the desired physical properties; surfactant solutions containing up to about 40% by weight of surfactant are operable, but are usually viscous enough that additional thickening is not required. At surfactant concentrations greater than 40% the solution viscosity is so great as to cause processing difficulty. More preferably the maximum concentration of surfactant is about 25% by weight. All surfactant concentrations are on a surfactant solids basis as a weight percentage of the total mixture.
• the thickener which contains free acid groups as it is prepared, be at least partially neutralized to the salt form prior to acidification of the mixture; it is further critical that the neutralized thickener be in the presence of the surfactant at the time the acidification occurs. While inadequately neutralized thickener is operable in the present invention, it is wasteful, because failure to adequately neutralize the thickener results in a reduced contribution of the unneutralized thickener to the mixture viscosity. Similarly, an excess of the neutralizing agent is undesirable, as it must react with the acidifying agent before the mixture pH can be adjusted to the desired, acidic level.
• the preferred amount of neutralizing agent is that amount required to adjust the mixture pH to above 6.5, and more preferably to between 7.0 and 7.5. This corresponds approximately to 0.5-0.8. equivalent of neutralizing agent per equivalent of acid groups in the thickener.
• the mixture may be acidified with any acid that is capable of reducing the pH to the desired level. The selection of the specific acid will ordinarily depend upon factors not related to the present invention. For example, in shampoo and cosmetic applications, low toxicity may be an important factor in acid selection, and citric acid is preferred in many such applications. Because the mixture contains a high concentration of organic components, the use of oxidizing acids for acidification is not preferred.
• foam stabilizers include the class of materials generally referred to as foam stabilizers. These include fatty acid alkanolamides, especially those in which the carboxyl group is substituted by a long-chain, preferably C 12 -C 22 , alkane, such as lauric diethanolamide, coconut acid diethanolamide and the like. These foam stabilizers are preferably present in the mixture at a level from about 0.5% to about 5% by weight, the exact amount being selected as that which prevents turbidity in the thickened, acidified solution.
• the thickened surfactant mixtures of the following examples were prepared according to the following procedure:
• the alkali-soluble emulsion is dispersed in deionized water.
• the major surfactant component is added and mixed, the alkanolamide is added, and finally the neutralizing agent, which is 0.5 equivalents of sodium hydroxide per equivalent of thickener carboxyl groups as a 10% aqueous solution, is added.
• the solution is mixed by stirring for about 15 minutes, and is allowed to stand overnight before the viscosity is measured.
• varying amounts of a 20% aqueous solution of citric acid is added to 50-g aliquots of the thickened surfactant solution until the desired pH is obtained.
• Viscosities given in the following examples were obtained using a Brookfield Model LVT Viscometer at the indicated spindle speed. It should be noted that the thickened solutions are pseudoplastic, or shear thinning, so that shear rate, as indicated herein by spindle speed, is an important parameter in viscosity measurement.
• Mixtures were prepared containing an anionic surfactant at varying levels and an alkali-soluble, ionic thickener of the present invention at a constant level, and viscosities of the mixtures were determined at various pH levels to establish the criticality of surfactant to the preservation of viscosity at low pH levels.
• the surfactant used was sodium lauryl sulfate, and the thickener was as described in the specification above, wherein component (1) is methacrylic acid (40%), component (2) is as represented by the general formula wherein R is CH 3 , n is 20 and R° is a mixture of C 16 and C 18 alkyls (10%), component (3) is ethyl acrylate (50%) and component (4) is not used.
• the mixture is neutralized with 0.8 equivalents of sodium hydroxide, and the neutralized mixture was acidified with citric acid.
• Mixtures containing 1.0% of the thickener and the indicated amount of sodium lauryl sulfate were prepared according to the above procedure, and acidified to the indicated pH.
• the viscosity at a spindle speed of 12 rpm was determined, and the results are given in Table I.
• the mixtures were prepared according to the procedure given above, and various pH levels of the mixtures were measured for viscosity at a spindle speed of 12 rpm.
• the composition of the mixtures is given in Table II, and the results are given in Table III.

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• Wood Science & Technology (AREA)
• Engineering & Computer Science (AREA)
• Detergent Compositions (AREA)
• Cosmetics (AREA)
• Polymerisation Methods In General (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Agricultural Chemicals And Associated Chemicals (AREA)
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Cited By (52)

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Citations (10)

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• 1982
  • 1982-03-17 US US06/358,993 patent/US4529773A/en not_active Expired - Lifetime
• 1983
  • 1983-03-14 DE DE8383301384T patent/DE3362231D1/de not_active Expired
  • 1983-03-14 AT AT83301384T patent/ATE18251T1/de not_active IP Right Cessation
  • 1983-03-14 EP EP83301384A patent/EP0089213B1/fr not_active Expired
  • 1983-03-16 CA CA000423761A patent/CA1203140A/fr not_active Expired
  • 1983-03-17 JP JP58043314A patent/JPS58189299A/ja active Granted
  • 1983-03-17 AU AU12540/83A patent/AU552193B2/en not_active Ceased

Patent Citations (10)

Non-Patent Citations (1)

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